MAX1698_07 Datasheet, PDF (1/8 Pages) Maxim Integrated Products – High-Efficiency Step-Up Current Regulator for LEDs

19-1621; Rev 2; 2/07
High-Efficiency Step-Up
Current Regulator for LEDs
General Description
The MAX1698 and MAX1698A are efficient drivers for
white or color LEDs. They are ideal for large LED backlit
displays in PDAs and laptop computers. Numerous
benefits include greater simplicity, lower cost, higher
efficiency, longer bulb life, and greater reliability when
compared to fluorescent (CCFL) and electrolumines-
cent (EL) lamps.
The MAX1698/MAX1698A are switch-mode boost con-
trollers in which LED current, rather than output voltage,
is regulated The devices drive series-connected LEDs
with a controlled current that is measured with a typical-
ly 15Ω sense resistor, not an expensive fractional-ohm
value. LED current control and dimming are accom-
plished with an adjust input (ADJ). For larger light out-
put, multiple LED banks can be connected in parallel
with up to 5W total output power.
The MAX1698A has a higher, and more accurately
specified, CS current limit than the MAX1698 for higher-
power applications of 5W or more. Both devices are
supplied in a space-saving 10-pin µMAX package that
occupies half the space of an 8-pin SO. An evaluation
kit (MAX1698EVKIT) is available to speed designs.
Applications
Battery-Powered Backlight Applications
Backlight for LCD Panels
Notebook PCs
Handy Terminals
PDAs
Features
♦ Over 90% Efficiency
♦ Lossless, Adjustable LED Brightness
♦ Space-Saving 10-Pin µMAX Package
♦ Simpler, Lower Cost, More Reliable Compared
to CCFL or EL Backlights
♦ Up to 5W Output Power
Ordering Information
PART
MAX1698EUB
MAX1698AEUB
TEMP RANGE ^PIN-
PACKAGE
-40°C to +85°C 10µMAX
-40°C to +85°C 10µMAX
PKG
CODE
U10-2
U10-2
TOP VIEW
Pin Configuration
V_CC 1
SHDN 2
REF 3
ADJ 4
GND 5
MAX1698
MAX1698A
10 EXT
9 CS
8 PGND
7 GND
6 FB
µMAX
L
V_BATT
V_CC
ON
OFF
V_CC
EXT
MAX1698
MAX1698A
SHDN
CS
REF
PGND
ADJ
FB
GND
Typical Operating Circuit
D1
V_OUT
C_OUT
I_LED
R_FB
R_N
________________________________________________________________ Maxim Integrated Products 1
For pricing delivery, and ordering information please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.